Centering attachment

ABSTRACT

Centering attachment for locating a machine component relative to a work piece of circular cross-section irrespective of diameter, including a pair of relatively movable elements adapted to engage circumferentially spaced portions of the work piece, and indicating surfaces on the elements adapted to form a smooth continuous surface when the component is properly spaced from the axis of the work piece.

United States Patent Bedker et a1.

[ 1 July 4, 1972 [54] CENTERING ATTACHMENT [72] Inventors: Bruce D. Bedker, Mt. Clemens; Frederich C. Wunderlich, Detroit, both of Mich.

[73] Assignee: Salvo Tool 8: Engineering Company,

Roseville, Mich.

[22] Filed: Dec. 9, 1970 [21] Appl. No.: 96,357

[52] US. Cl ....72/35, 33/169 C, 33/185 R [51] Int. Cl ..B2lh 1/00 [58] Field ofSearch ..72/31,32, 35,36,125;

33/169 C, 172 D, 180 R, 185 R; 408/75 [56] References Cited UNITED STATES PATENTS 2,621,420 12/1952 Brelsford ..33/185 Smutny ..33/185 Gill ..33/185 Primary Examiner-Lowell A. Larson Atl0meyWhittemore, Hulbert & Belknap [57] ABSTRACT Centering attachment for locating a machine component relative to a work piece of circular cross-section irrespective of diameter, including a pair of relatively movable elements adapted to engage circumferentially spaced portions of the work piece, and indicating surfaces on the elements adapted to form a smooth continuous surface when the component is properly spaced from the axis of the work piece.

17 Claims, 12 Drawing Figures PMENTEDJUL 4:912 3,673,832

i INVENTORS.

PATENTEUJUL 41972 3,673,832

' saw 20? 2 WW W 1 24 no:

CENTERING ATTACHMENT BRIEF SUMMARY OF THE INVENTION The present invention is applicable to many types of machine tools or other instruments, but is illustrated as applied to a machine tool having a slide movable toward and away from a cylindrical work piece in a direction radial thereof. A good example of such a machine is a thread rolling machine in which threads are rolled on cylindrical stock by means of a pair of spaced rolls movable in straddling relation over the rotating work piece. A thread rolling attachment of this kind is illustrated in Bedker patent 2,690,089. In a thread rolling attachment of this sort it is essential for the slide which carries the thread rolling attachment to advance to an accurately predetermined position in which the thread rolls stop just short of a fully centered position.

In accordance with the present invention, the thread rolling or other machining attachment is removed from the slide and the fixture of the present invention is mounted in its place. In specific detail, the centering or gauging fixture comprises a first pivoted arm having an inclined surface engageable with a side of the work piece. Normally, the arm is pivoted to swing in a vertical plane and engages the work piece at one of the upper quadrants. Pivoted to the arm is a gauging blade having a surface which engages the adjacent upper quadrant of the work piece. When the slide on which the centering attachment is mounted is in the position corresponding to exact on-center position with respect to the work piece, the movable blade will have moved into a position such that one or more surfaces thereof coincides precisely with a directly adjacent surface of the arm. This permits the operator to determine when the oncenter position is reached by feeling these gauge surfaces. This is particularly useful since in many cases the centering attachment will be concealed or at least rendered difficult to observe by parts of the machine tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of the centering attachment base.

FIG. 2 is a side elevational view of the base.

FIG. 3 is a plan view of the base.

FIG. 4 is an elevational view of the arm.

FIG. 5 is an elevational view of the blade.

FIG. 6 is a sectional view through the arm on the line 6-6, FIG. 4.

FIG. 7 is a sectional view through the blade on the line 7-7,

FIG. 5.

FIG. 8 is an elevational view of the assembly in position with respect to a work piece.

FIG. 9 is a view similar to FIG. 8 showing the attachment brought into centered relation from the position occupied in FIG. 8.

FIG. 10 is a view similar to FIG. 9 showing the relationship of parts when the attachment is moved beyond centered relation from the position illustrated in FIG. 8.

FIG. 11 is a view showing the attachment indicating correct centered relationship with a work piece of smaller diameter than shown in FIGS. 8-10.

FIG. 12 is a view of a somewhat differently shaped arm and blade attached to the supporting block in position at 90 from that illustrated in FIG. 8.

DETAILED DESCRIPTION The centering attachment is adapted to be mounted on a slide, which is not illustrated in the present case, in place of a piece of tooling such for example as a thread roll. The centering attachment is carefully dimensioned so that it will indicate a true centered position of the tooling when the slide is in a predetermined position, the correctness of which is indicated by the centering attachment.

Inasmuch as the attachment is capable of use with different diameter work pieces, it is of course essential that the blade and arm be so designed as to register correct centered position independent of the diameter of the work piece.

The conventional tooling for which the centering attachment is substituted is received in a dovetail on the slide and different tooling assemblies are provided with two different dovetail widths. Accordingly, the base 10 illustrated in FIGS. 1-3 has its opposite sides inclined, the long sides being indicated at 12 and the short sides at 14. Thus, the centering attachment may be mounted in either of the dovetail arrangements.

In either case, it is desirable to position the centering attachment so that the arm and blade swing in a vertical plane and hence are adapted to be urged by gravity downwardly into contact with opposite sides of the upper half of the cylindrical work piece. The base 10 is provided with a forwardly projecting portion 15 provided with a slot 16, the slot having an arcuate bottom 18 as a result of the method of forming the slot. The material of the projecting portion 15 above the slot 16 is apeitured as indicated at 20, and a partially cylindrical recess 22 is provided for the reception of the head of an assembly screw as will later appear.

In line with the opening 20, the projecting portion 15 below the slot 16 has a tapped recess 24 for the reception of the threaded portion of the assembly screw.

The forwardly projecting portion 15 of the base includes a further projecting portion 26 and this portion 26 is provided with a slot 28 which extends at right angles to the slot 16. The slot 28 has an arcuately curved bottom surface 30 as best seen in FIG. 2, and is further provided with a recessed portion 32.

Below the slot 28 as illustrated in FIG. 3, there is provided an enlarged opening 34 and in line with this opening in the projecting portion 26 above the slot 28 is the tapped opening 36.

Adapted to be assembled with the base 10 in one or the other of the two slots is an arm 40 having an opening 42 at one end. The arm 40 is formed with a downwardly facing recess which as illustrated is bounded at one side by a straight or fiat surface 44 and at the other side by a concavely curved gauging surface 45. The upper edge of the arm 40 is provided with a flat indicating surface 46. The surface 45 as will subsequently appear, is adapted to engage the cylindrical surface of the work piece and is preferably provided with a narrow land 47 having a width for example of about 0.0l0 inch, the balance of the surface being inclined slightly as indicated at 48, the angle of inclination being for example about 3.

The arm 40 is provided with a tapped opening 49 and a blade 50 is adapted to be pivotally connected to the arm 40 by a screw engaging in the opening 49. The blade 50 includes the opening 52 by means of which it is pivoted to the arm and is provided with a generally straight gauging surface 54 which is also adapted to engage the surface of the work piece at a point circumferentially spaced from the point of engagement by the arm 40. Again, since the surface 54 is a gauging surface it is provided with a relatively narrow land 55 having a width for example of about 0.010 inch. The remainder of the surface 54 is inclined or relieved as for example at an angle of about 3 as indicated at 56. Provided on the blade 50 is an indicating pro.- jection 58 having a surface 59 which when the centering attachment indicates proper centering with respect to the work piece, will be flush with the upper surface of the arm 40 so that the operator may detemiine this condition to exist by feeling the surface 59 and its relationship to the adjacent upper surface of the arm 40.

Referring now to FIG. 8 there is illustrated a condition in which the centering attachment including its base 10, is located too far to the left from the vertical center line passing through the work piece W. At this time the concave surface 45 of the arm 40 engages the surface of the work piece in the upper right hand quadrant as indicated substantially at 60, and this of course determines the position of the arm 40, which is permitted to pivot about the assembly screw 62 received in the recess 32 and threaded opening 36. At this time the blade 50 will have swung downwardly about a screw 64 by means of which it is pivoted to the arm 40. In this condition, which represents a gross displacement from the centered position, it

will be observed that the projection 58 is substantially below the indicating surface 46 of the arm 40.

Referring now to FIG. 9 there is illustrated the condition in which the slide to which the centering attachment is mounted, has been moved to the right to the position corresponding precisely to the centered position with reference to the work piece W. At this time the curved surface 45 of the arm 40 engages the cylindrical surface of the work piece in its upper right hand quadrant approximately at the point 66. The blade 50 will have been swung about the pivot 64 so that the surface 59 will have been swung about the pivot 64 so that the surface 59 of projection 58 is exactly flush with the indicating surface 46 of the arm 40. This condition can readily be felt by the operator by placing his finger on the top of the projection 58 and observing the smooth continuation of the surfaces 46 and 59.

Referring now to F 1G. there is illustrated the condition in which the slide supporting the centering attachment has-been moved too far to the right from the correctly centered position illustrated in FIG. 9. At this time the surface 44 of the arm 40 hasengaged the work piece W, swinging the arm 40 upwardly about pivot 62 and bringing the concave surface 45 into clearance with respect to the work piece. At this time the blade 50 will have been swung clockwise about its pivot 64 with reference to the arm 40 to cause the projection 58 thereon to extend above the indicating surface 46 of the arm.

Referring now to F 1G. 1 1 there is illustrated the same structure in association with a work piece Wa which is of substantially smaller diameter. At this time the concavely curved surface 45 of the arm 40 engages the smaller diameter work piece Wa substantially at the point 68 and the blade 50 engages the work piece Wa and has been swung thereby to bring the top surface 59 of its projection 58 into parallelism with the indicating surface 46 of the arm 40.

In order for the centering attachment to work precisely with different diameter work pieces it is essential for the curved concave surface 45 to be accurately developed such that the centered conditions illustrated in FIGS. 9 and 11 occur irrespective of the diameter of the work piece. This can readily be accomplished graphically by laying out the parts on an enlarged scale.

It will of course be understood that while in the present instance the surface 45 is illustrated as concavely curved and the gauging surface 54 of the blade is illustrated as a straight surface, this relationship could be reversed or if desired, both surfaces could be curved. The only essential requirement is that as the arm engages the work piece while in centered position, the blade shall also be engaged by the work piece and moved relative to the arm to the position in which its indicating surface 59 is flush or coplanar with the indicating surface 46.

Referring now to FIG. 12 there is illustrated the assembly of a blade 70 to an arm 72 using the base 10 in its alternative position, the arm 72 being pivoted to the base 10 by a screw indicated at 74 received in the opening 20. The blade 70 is pivoted to the arm 72 by a pivot member 76. The parts are illustrated in proper centered relation with respect to a work piece Wb, this condition being indicated by the flush relationship of the indicating surface 78 of the blade 70 with respect to the adjacent surface 80 of the arm. In this case the blade 70 is provided with a second indicating surface 82 which when the parts are in centered condition is coplanar with the adjacent surface 84 on the arm 72. As before, the arm 72 is provided with a concave gauging surface 86 while the blade 70 is provided with an essentially straight gauging surface 88.

What we claim as our invention is:

l. A centering attachment for use with a part of circular cross-section comprising a base movable in a first direction generally-radial of the part between positions corresponding to either side of centered position and through an exactly centered position, an arm on said base having a gauge surface engageable with the. part and inclined to the first direction of movement, means mounting said arm for movement on said base in a first plane generally transverse to the axis of the part and m a second direction transverse to said first direction, a

blade movably carried by said arm and having a gauge surface engageable with the partwhich is oppositely inclined to said first direction from the inclination of the part-engaging surface on said arm, said blade being movable on said arm in a second plane parallel to said first plane and in a third direction transverse to said first direction, and cooperating indicating means on said arm and blade operable to indicate a relative position between said arm and blade in which said base occupies a position corresponding to correctly centered position.

2. A centering attachment as defined in claim 1 in which said arm is pivoted to said base.

3. A centering attachment as defined in claim 2 in which the pivot axis of said arm is parallel to the axis of the part.

4. A centering attachment as defined in claim 3 in which the gauge surface on said arm is shaped relative to the gauge surface on said blade such that the centering attachment operates with different identically located parts of different diameters.

5. A centering attachment as defined in claim 4 in which one of said gauge surfaces is a plane surface and the other gauge surface is a concave surface.

6. A centering attachment as defined in claim 5 in which the gauge surface on said arm is the concave gauge surface.

7. A centering attachment as defined in claim 2 in which said blade is pivoted to said arm.

8. A centering attachment as defined in claim 7 in which the pivot axis of said arm is parallel to the axis of the part.

9. A centering attachment as defined in claim 7 in which the gauge surface on said arm is shaped relative to the gauge surface on said blade such that the centering attachment operates with difierent identically located parts of different diameters.

10. A centering attachment as defined in claim 7 in which one of said gauge surfaces is a plane surface and the other gauge surface is a concave surface.

11. A centering attachment as defined in claim 10 in which the gauge surface on said arm is the concave gauge surface.

12. A centering attachment as defined in claim 7 in which said gauge surfaces converge to define a recess facing the part in which the part is received during a centering operation in contact with one or both of said gauge surfaces.

13. A centering attachment as defined in claim 2 in which said base is provided with pivot mounting means disposed at right angles to each other, for supporting said arm, and is shaped to be supported in use with the axis of either of said pivot mounting means parallel to the part axis.

14. A centering attachment for use with a part of circular cross-section comprising a base movable in a first direction generally radial of the part between positions corresponding to either side of centered position and through an exactly centered position, an arm pivoted to said base for swinging movement in a plane perpendicular to the axis of the part, said arm having a first inclined gauging surface engageable with the side of the part remote from the pivot axis of said arm, a blade pivoted to said arm and having a second gauging surface oppositely inclined with respect to the inclination of said first gauging surface and engageable with the side of, the part adjacent the pivot axis of said arm, and an indicator surface at the edge of said blade opposite its gauging surface positioned to become coplanar with the adjacent edge surface of said arm when said pivot axis of said arm is spaced from the axis of the part a distance corresponding to a predetermined centered condition.

15. A centering attachment as defined in claim 14 in which one of said gauging surfaces is concave and one is straight.

16. A centering attachment as defined in claim 15 in which the gauge surface on said arm is the concave gauge surface.

17. A centering attachment as defined in claim 14 in which said gauge surfaces each comprise a narrow land having a width of a few thousandths of an inch, the remainder of the surface being relieved at a small angle.

10* I I I 

1. A centering attachment for use with a part of circular crosssection comprising a base movable in a first direction generally radial of the part between positions corresponding to either side of centered position and through an exactly centered position, an arm on said base having a gauge surface engageable with the part and inclined to the first direction of movement, means mounting said arm for movement on said base in a first plane generally transverse to the axis of the part and in a second direction transverse to said first direction, a blade movably carried by said arm and having a gauge surface engageable with the part which is oppositely inclined to said first direction from the inclination of the part-engaging surface on said arm, said blade being movable on said arm in a second plane parallel to said first plane and in a third direction transverse to said first direction, and cooperating indicating means on said arm and blade operable to indicate a relative position between said arm and blade in which said base occupies a position corresponding to correctly centered position.
 2. A centering attachment as defined in claim 1 in which said arm is pivoted to said base.
 3. A centering attachment as defined in claim 2 in which the pivot axis of said arm is parallel to the axis of the part.
 4. A centering attachment as defined in claim 3 in which the gauge surface on said arm is shaped relative to the gauge surface on said blade such that the centering attachment operates with different identically located parts of different diameters.
 5. A centering attachment as defined in claim 4 in which one of said gauge surfaces is a plane surface and the other gauge surface is a concave surface.
 6. A centering attachment as defined in claim 5 in which the gauge surface on said arm is the concave gauge surface.
 7. A centering attachment as defined in claim 2 in which said blade is pivoted to said arm.
 8. A centering attachment as defined in claim 7 in which the pivot axis of said arm is parallel to the axis of the part.
 9. A centering attachment as defined in claim 7 in which the gauge surface on said arm is shaped relative to the gauge surface on said blade such that the centering attachment operates with different identically located parts of different diameters.
 10. A centering attachment as defined in claim 7 in which one of said gauge surfaces is a plane surface and the other gauge surface is a concave surface.
 11. A centering attachment as defined in claim 10 in which the gauge surface on said arm is the concave gauge surface.
 12. A centering attachment as defined in claim 7 in which said gauge surfaces converge to define a recess facing the part in which the part is received during a centering operation in contact with one or both of said gauge surfaces.
 13. A centering attachment as defined in claim 2 in which said base is provided with pivot mounting means disposed at right angles to each other, for supporting said arm, and is shaped to be supported in use with the axis of either of said pivot moUnting means parallel to the part axis.
 14. A centering attachment for use with a part of circular cross-section comprising a base movable in a first direction generally radial of the part between positions corresponding to either side of centered position and through an exactly centered position, an arm pivoted to said base for swinging movement in a plane perpendicular to the axis of the part, said arm having a first inclined gauging surface engageable with the side of the part remote from the pivot axis of said arm, a blade pivoted to said arm and having a second gauging surface oppositely inclined with respect to the inclination of said first gauging surface and engageable with the side of the part adjacent the pivot axis of said arm, and an indicator surface at the edge of said blade opposite its gauging surface positioned to become coplanar with the adjacent edge surface of said arm when said pivot axis of said arm is spaced from the axis of the part a distance corresponding to a predetermined centered condition.
 15. A centering attachment as defined in claim 14 in which one of said gauging surfaces is concave and one is straight.
 16. A centering attachment as defined in claim 15 in which the gauge surface on said arm is the concave gauge surface.
 17. A centering attachment as defined in claim 14 in which said gauge surfaces each comprise a narrow land having a width of a few thousandths of an inch, the remainder of the surface being relieved at a small angle. 